/Engine/Source/Editor/SequencerCore/Public/MVVM/ViewModels/ViewModelHierarchy.h
Called before a change is made to the specified model's parent or previous sibling
void PreHierarchicalChange ( const [TSharedPtr](API\Runtime\Core\Templates\TSharedPtr)< [FViewModel](API\Editor\SequencerCore\MVVM\ViewModels\FViewModel) > & InChangedNode )